As large increase of smart terminals, in further evolution of a future long-term evolution-advanced (LTE-Advanced) system, it is possible that a conventional macro eNB (macro eNB) cannot deal with demands for rapidly-increased capacities and peak-value rates. By further deploying eNBs more densely, a user is made to be more physically close to an eNB, thereby increasing a system capacity, increasing a peak-value rate, and improving user terminal experiences. However, deployment of a macro eNB with large power will result in problems of over high cost, and non-green communications, etc. Therefore, people have begun to take small eNBs (small eNBs) with low power into consideration, such as a pico cell (pico eNB), a femto cell (femto eNB), and a RRH (remote radio head), etc. A small eNB has comprehensively advantageous over a macro eNB as it is low in cost, fast and flexible in deployment, and high in cost performance ratio. Hence, a small eNB is very suitable for use in an outdoor hotspot, increases a network capacity, improves indoor depth coverage, and improves user perception. Therefore, more and more attention shall be paid to small eNBs in the industry. In a future LTE-Advanced network, the number of small eNBs will exceed that of conventional macro eNBs.
The coverage of a small eNB is less than that of a macro eNB, and higher available bands, such as 3.5 GHz, may be used, while a macro eNB follows using existing relatively low bands to provide a relatively large and robust coverage. For user equipment (UE) supporting multiple carrier aggregation (CA), both a macro eNB and a small eNB may be configured for the UE, which operate at different frequencies, i.e. different carrier components (CCs). Small eNBs may be in the coverage of a macro eNB, and small eNBs may also be out of the coverage of a macro eNB. Small eNBs may be deployed sparsely or densely. Small eNBs may appear in forms of clusters, that is, small eNBs physically close to each other are divided into one cluster. In the same cluster, each small eNB may be connected to the same eNB (evolved Node B). Then, a backhaul between each small eNB in the cluster may be deemed as being ideal, such as being less in time delay, and being capable in transmission. While in the coverage of a macro eNB, different clusters may be connected to different eNBs or to the same eNB. FIG. 1 is a schematic diagram of joint deployment of a small eNB and a macro eNB. As shown in FIG. 1, F2 is used to deploy a small eNB, and F1 is used to deploy a macro eNB.
It was found by the inventors in the implementation of the present application, when UE moves between small eNBs in the same cluster, if a conventional cell handover procedure is still followed, the UE will be in a state of frequent handover, which increases loads at the UE side, and a large amount of unnecessary information is interacted between the UE and an eNB and between eNBs.
It should be noted that the above description of the background art is merely provided for clear and complete explanation of the present application and for easy understanding by those skilled in the art. And it should not be understood that the above technical solution is known to those skilled in the art as it is described in the background of the present application.